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Root lesion nematode of tea (Pratylenchus loosi) is one of the most dangerous and destructive pests in all areas of the world where tea grows. Rhizobacteria with nematicidal properties were screened using the soils of root lesion nematode-infected tea fields located in Guilan province, Iran. Effective bacteria were identified based on molecular and biochemical methods. Protease enzyme production was investigated on skim milk agar (1%) medium. The effects of temperature and pH on the amount of protease production by bacteria were investigated. Three protease inhibitors, namely PMSF, EDTA and 1,10-phenanthroline, were investigated. In total, 150 bacterial strains were isolated from tea rhizosphere using the spread-plating technique and nutrient agar medium, of which four bacterial isolates of Pseudomonas spp. had nematicidal properties in the range of 84.98% to 95.24%. Two of the bacterial isolates, RH25 (Pseudomonas aeruginosa) and RH37 (Pseudomonas fluorescens), had the largest clear zone of proteolysis on skim milk agar and were subjected to various biochemical tests. The influences of time (1 to 120 h), temperature (22 to 37°C) and pH (7.0 to 8.5) were investigated in the production of protease. The highest enzyme production was obtained from growing RH37 and RH25 on mineral medium when incubated at temperatures of 26°C and 30°C for 72 and 96 h and at initial pH values of 7.2 and 7.6, respectively. Proteases obtained from RH37 (P. fluorescens) belonged to the metalloprotease and serine protease families and the one produced by RH25 (P. aeruginosa) was a metalloprotease. According to the results of this research, the most effective control mechanism of these bacteria against nematodes is the production of bacterial protease. This mechanism can be exploited to control nematodes. [ABSTRACT FROM AUTHOR]

e rice blast disease caused by Pyricularia oryzae Cavara is among the most severe plant diseases in the world. e utilization of natural antagonists, such as fungal endophytes, can be a good method to control the spread of this disease. In the present study, 68 fungal isolates were obtained from 160 rice samples collected in Guilan province fields, Iran. Morphological and molecular characteristics were used for the identification of these fungi. According to the results, the fungal isolates were Alternaria citri (Penz.) Mussat, Alternaria infectoria Simmons, Aspergillus fumigatus Fresen, Fusarium verticillioides (Sacc.) Nirenberg, Trichoderma harzianum Rifai, Trichoderma virens (Mill., Giddens & Foster) Arx, Trichoderma viride Pers., Ulocladium consortiale (um) Simmons, and Pyricularia oryzae. Eight isolates that did not cause any plant disease were selected for biocontrol studies in vitro. e dual culture, culture filtrate, slide culture, and volatile metabolites methods were used in search of natural endophytic antagonists of Pyricularia oryzae. It was found that T. harzianum, T. virens, T. viride, A. fumigatus, and A. citri isolates caused the highest percentage of mycelial growth inhibition of P. oryzae in vitro. In the greenhouse experiments, all of the studied isolates reduced the P. oryzae disease rating, with T. harzianum isolate being the most effective antagonist (27.36% reduction in the disease rating), followed by T. virens, T. viride, and A. fumigatus (20.75%, 17.92%, and 16.98%, respectively). Furthermore, in greenhouse conditions, these antagonistic fungi increased the height, fresh weight, and dry weight of plants. e results of this research showed that there are various fungi in the natural flora of rice plants that possess potential biological properties against rice blast disease that can be implemented into practice. [ABSTRACT FROM AUTHOR]

Chamaecyparis lawsonia, which brings beauty in parks and green space, is attacked by a variety of pathogenic agents specially fungi. In this study, some Chamaecyparis lawsonia available in parks that had disease symptoms were sampled. After sample collection, in order to isolate fungal pathogens, cuts of the infected plant tissues were placed on PDA (potato dextrose agar) and later were put on WA (water agar) for identifying. Then test of pathogenicity of these isolates on Chamaecyparis lawsonia was done inside the box with plastic stopper. To do this, cuts of colonies of 4 day fungi obtained on PDA medium were put on leaves. The final evaluation was performed after 10 days. This experiment was performed in a completely randomized design with 3 replications and 7 treatments. The results showed that isolated fungi are in 2 groups as following: Alternaria franseriae and Alternaria tenuissima. According to the results, both species were pathogenic on host. Totally, A. franseriae showed more disease severity compared to A. tenuissima on C. lawsonia. [ABSTRACT FROM AUTHOR]

In this research during 2011-12, Colletotrichum graminicola was isolated from Echinochloa spp. and studied as a biological agent for control. At first, reactions of five rice cultivars to C. graminicola were evaluated. Then, C. graminicola was inoculated on Echinochloa spp. Results indicated that the disease rating caused by this fungus in the weed was more than that in the studied rice cultivars. Also, the fungus had a significant effect on the height, fresh weight and dry weight of Echinochloa spp. and reduced them. So, C. graminicola is not recommended as a probable mycoherbicide for biological control of Echinochloa spp. in paddy fields. [ABSTRACT FROM AUTHOR]

Optimal operating parameters of 2,3-Butanediol production using Klebsiella oxytoca under submerged culture conditions are determined by using Taguchi method. The effect of different factors including medium composition, pH, temperature, mixing intensity, and inoculum size on 2,3-butanediol production was analyzed using the Taguchi method in three levels. Based on these analyses the optimum concentrations of glucose, acetic acid, and succinic acid were found to be 6, 0.5, and 1.0 (% w/v), respectively. Furthermore, optimum values for temperature, inoculum size, pH, and the shaking speed were determined as 37°C, 8 (g/L), 6.1, and 150 rpm, respectively. The optimal combinations of factors obtained from the proposed DOE methodology was further validated by conducting fermentation experiments and the obtained results revealed an enhanced 2,3-Butanediol yield of 44%. [ABSTRACT FROM AUTHOR]